SUMMARY OF PROPOSAL 61090

NGC 5322: A YOUNG ELLIPTICAL/OLD MERGER CANDIDATE

ABSTRACT

NGC 5322 is an elliptical galaxy whose optical colour and sub-structure (massive counter-rotating core; fine structure) make it a strong candidate for an ancient merger (~5 Gyrs ago) of two spirals (Schweizer and Seitzer 1992). Such candidate young ellipticals are rare, and their X-ray spectra tell us about the balance of energetics during a merger: is gas heated and lost in a wind, or retained as an X-ray bright halo or cooling flow?. The scatter in the X-ray-to-optical luminosity correlation for ellipticals may be explained by different formation processes, including merging of galaxy pairs. We will test for the presence and temperature of any hot gas in NGC 5322 with a deep ASCA observation. Joint spectral fits with ROSAT PSPC data will further constrain the spectrum.